1. Field of the Invention
The present invention relates to an optical system capable of correcting an image position and, more particularly, to an objective lens system suitable for SLR cameras (Single-Lens Reflex cameras), electronic cameras, and video cameras.
2. Related Background Art
In the present specification, an operation for correcting any variation of an image position caused by a focusing operation, a camera shake, or the like by displacing a predetermined lens group in a direction substantially perpendicular to the optical axis will be referred to as "image position correction".
As a conventional optical system capable of correcting an image position of this type, an optical system disclosed in U.S. Pat. No. 4,978,205 is known. In the optical system disclosed in U.S. Pat. No. 4,978,205, an optical member closest to the object side consists of an anamalous dispersion glass (ED glass) material. Since the ED glass material is soft, a surface, closest to the object side, of the optical system is undesirably easily damaged.